Various processes and catalysts have been disclosed for producing polyalkylene polyamines, including those disclosed in the patents listed below. These listed U.S. patents have been considered with reference to patentability of the invention disclosed and claimed herein. However, they are not considered sufficiently relevant for separate comment.
U.S. Pat. No. 4,103,087--Brennan PA1 U.S. Pat. No. 4,123,462--Best PA1 U.S. Pat. No. 4,061,633--Blyakhman et al PA1 U.S. Pat. No. 3,270,059--Winderl et al PA1 U.S. Pat. No. 3,037,023--Moss et al PA1 U.S. Pat. No. 3,565,957--Mirviss et al PA1 U.S. Pat. No. 3,281,470--Vertnik PA1 U.S. Pat. No. 2,519,803--Weber et al PA1 U.S. Pat. No. 3,255,248--Suesengoth et al PA1 U.S. Pat. No. 3,427,356--Baer et al
With regard to the preparation of higher polyalkylene polyamines by reaction of lower polyalkylene polyamines, British Pat. No. 1,500,220 of the Texaco Development Corporation is of specific interest. According to that patent, predominantly non-cyclic polyamines are formed by reaction of lower polyalkylene polyamines with alkanol amines under elevated temperature and pressure conditions, with a phosphorus-containing catalyst. Among the suitable catalysts are "acidic metal phosphates [including] boron phosphate, ferric phosphate, and aluminum phosphate", (Col. 3, lines 27-29). That patent further teaches, and Examples II and III thereof demonstrate, that the process there taught requires "an alkylating material such as an ethanolamine compound in the process of the invention", (Col. 5, lines 55-59).
With this background in mind, it is the general object of the present invention to provide a practical and economical process for producing various polyalkylene polyamines.